The testing of the functional systems of automobiles, trucks and the like has progressed to the point that extremely sophisticated and detailed tests may be performed to insure both that the components of an automobile are working properly from a mechanical and electro-mechanical point of view, and that system performance is in accordance with mandated guidelines, whether they be on the federal, state or local level. The federal Environmental Protection Administration (EPA), for example, has promulgated extensive regulations limiting the emissions of motor vehicles. Typically, a battery of tests may be performed by a test technician utilizing computer-controlled interface and analysis system which provides essentially real time evaluation of the parameters under test.
One area in which test technology has lagged, however, is in the analysis of the system and components utilized to control fuel evaporation to the atmosphere from the fuel tank and associated piping. Such loss of fuel is both wasteful and environmentally unsound, as the evaporated fuel, in addition to creating a possibly dangerous situation, contributes to unwanted hydrocarbon pollution. Indeed, the EPA has imposed requirements that vehicle fuel evaporation control systems be inspected for proper performance. Typically, however, such inspections have been conducted manually, without the benefit of automated test procedures which would simplify the inspection and provide more reliable and consistent testing. In co-pending application Ser. No. 839,318 of Feb. 20, 1992 by the present invention, a method and system are disclosed for testing the integrity of the fuel evaporation control system of a vehicle. The testing is performed by the application of a pressure source to the fuel tank inlet. The removed fuel tank cap is thus not subject to testing. As the E.P.A. has identified fuel cap leaks as a main contributor to hydrocarbon emissions from passenger vehicles, the testing of fuel caps is an important anti-pollution action.
It is accordingly a purpose of the present invention to provide a method and apparatus for testing the integrity of a vehicle fuel tank cap.
Yet a further purpose of the present invention is to provide such an apparatus and method which permits testing to be conducted in an automated, non-intrusive manner.
Still a further purpose of the present invention is to provide such a method and apparatus which may be incorporated into existing test systems and test routines.
Still another purpose of the present invention is to provide such a method and apparatus which can provide both qualitative and quantitative measurements relating to the condition of the fuel tank cap.